The optional Xpos argument determines the horizontal
position of the dialog box in the viewing screen. It is the number of
twips from the left side of the screen to the left edge of the dialog
box. Twips are a graphical value used to set the ScaleMode property
of an object.

Ypos

The optional Ypos argument determines the vertical position
of the dialog box in the viewing screen. It is the number of twips from
the top of the screen to the top edge of the dialog box. Twips are a
graphical value used to set the ScaleMode property of an object.